1#ifndef __CEPH_DECODE_H
2#define __CEPH_DECODE_H
3
4#include <linux/err.h>
5#include <linux/bug.h>
6#include <linux/time.h>
7#include <asm/unaligned.h>
8
9#include <linux/ceph/types.h>
10
11/*
12 * in all cases,
13 *   void **p     pointer to position pointer
14 *   void *end    pointer to end of buffer (last byte + 1)
15 */
16
17static inline u64 ceph_decode_64(void **p)
18{
19	u64 v = get_unaligned_le64(*p);
20	*p += sizeof(u64);
21	return v;
22}
23static inline u32 ceph_decode_32(void **p)
24{
25	u32 v = get_unaligned_le32(*p);
26	*p += sizeof(u32);
27	return v;
28}
29static inline u16 ceph_decode_16(void **p)
30{
31	u16 v = get_unaligned_le16(*p);
32	*p += sizeof(u16);
33	return v;
34}
35static inline u8 ceph_decode_8(void **p)
36{
37	u8 v = *(u8 *)*p;
38	(*p)++;
39	return v;
40}
41static inline void ceph_decode_copy(void **p, void *pv, size_t n)
42{
43	memcpy(pv, *p, n);
44	*p += n;
45}
46
47/*
48 * bounds check input.
49 */
50static inline int ceph_has_room(void **p, void *end, size_t n)
51{
52	return end >= *p && n <= end - *p;
53}
54
55#define ceph_decode_need(p, end, n, bad)			\
56	do {							\
57		if (!likely(ceph_has_room(p, end, n)))		\
58			goto bad;				\
59	} while (0)
60
61#define ceph_decode_64_safe(p, end, v, bad)			\
62	do {							\
63		ceph_decode_need(p, end, sizeof(u64), bad);	\
64		v = ceph_decode_64(p);				\
65	} while (0)
66#define ceph_decode_32_safe(p, end, v, bad)			\
67	do {							\
68		ceph_decode_need(p, end, sizeof(u32), bad);	\
69		v = ceph_decode_32(p);				\
70	} while (0)
71#define ceph_decode_16_safe(p, end, v, bad)			\
72	do {							\
73		ceph_decode_need(p, end, sizeof(u16), bad);	\
74		v = ceph_decode_16(p);				\
75	} while (0)
76#define ceph_decode_8_safe(p, end, v, bad)			\
77	do {							\
78		ceph_decode_need(p, end, sizeof(u8), bad);	\
79		v = ceph_decode_8(p);				\
80	} while (0)
81
82#define ceph_decode_copy_safe(p, end, pv, n, bad)		\
83	do {							\
84		ceph_decode_need(p, end, n, bad);		\
85		ceph_decode_copy(p, pv, n);			\
86	} while (0)
87
88/*
89 * Allocate a buffer big enough to hold the wire-encoded string, and
90 * decode the string into it.  The resulting string will always be
91 * terminated with '\0'.  If successful, *p will be advanced
92 * past the decoded data.  Also, if lenp is not a null pointer, the
93 * length (not including the terminating '\0') will be recorded in
94 * *lenp.  Note that a zero-length string is a valid return value.
95 *
96 * Returns a pointer to the newly-allocated string buffer, or a
97 * pointer-coded errno if an error occurs.  Neither *p nor *lenp
98 * will have been updated if an error is returned.
99 *
100 * There are two possible failures:
101 *   - converting the string would require accessing memory at or
102 *     beyond the "end" pointer provided (-ERANGE)
103 *   - memory could not be allocated for the result (-ENOMEM)
104 */
105static inline char *ceph_extract_encoded_string(void **p, void *end,
106						size_t *lenp, gfp_t gfp)
107{
108	u32 len;
109	void *sp = *p;
110	char *buf;
111
112	ceph_decode_32_safe(&sp, end, len, bad);
113	if (!ceph_has_room(&sp, end, len))
114		goto bad;
115
116	buf = kmalloc(len + 1, gfp);
117	if (!buf)
118		return ERR_PTR(-ENOMEM);
119
120	if (len)
121		memcpy(buf, sp, len);
122	buf[len] = '\0';
123
124	*p = (char *) *p + sizeof (u32) + len;
125	if (lenp)
126		*lenp = (size_t) len;
127
128	return buf;
129
130bad:
131	return ERR_PTR(-ERANGE);
132}
133
134/*
135 * struct ceph_timespec <-> struct timespec
136 */
137static inline void ceph_decode_timespec(struct timespec *ts,
138					const struct ceph_timespec *tv)
139{
140	ts->tv_sec = (__kernel_time_t)le32_to_cpu(tv->tv_sec);
141	ts->tv_nsec = (long)le32_to_cpu(tv->tv_nsec);
142}
143static inline void ceph_encode_timespec(struct ceph_timespec *tv,
144					const struct timespec *ts)
145{
146	tv->tv_sec = cpu_to_le32((u32)ts->tv_sec);
147	tv->tv_nsec = cpu_to_le32((u32)ts->tv_nsec);
148}
149
150/*
151 * sockaddr_storage <-> ceph_sockaddr
152 */
153static inline void ceph_encode_addr(struct ceph_entity_addr *a)
154{
155	__be16 ss_family = htons(a->in_addr.ss_family);
156	a->in_addr.ss_family = *(__u16 *)&ss_family;
157}
158static inline void ceph_decode_addr(struct ceph_entity_addr *a)
159{
160	__be16 ss_family = *(__be16 *)&a->in_addr.ss_family;
161	a->in_addr.ss_family = ntohs(ss_family);
162	WARN_ON(a->in_addr.ss_family == 512);
163}
164
165/*
166 * encoders
167 */
168static inline void ceph_encode_64(void **p, u64 v)
169{
170	put_unaligned_le64(v, (__le64 *)*p);
171	*p += sizeof(u64);
172}
173static inline void ceph_encode_32(void **p, u32 v)
174{
175	put_unaligned_le32(v, (__le32 *)*p);
176	*p += sizeof(u32);
177}
178static inline void ceph_encode_16(void **p, u16 v)
179{
180	put_unaligned_le16(v, (__le16 *)*p);
181	*p += sizeof(u16);
182}
183static inline void ceph_encode_8(void **p, u8 v)
184{
185	*(u8 *)*p = v;
186	(*p)++;
187}
188static inline void ceph_encode_copy(void **p, const void *s, int len)
189{
190	memcpy(*p, s, len);
191	*p += len;
192}
193
194/*
195 * filepath, string encoders
196 */
197static inline void ceph_encode_filepath(void **p, void *end,
198					u64 ino, const char *path)
199{
200	u32 len = path ? strlen(path) : 0;
201	BUG_ON(*p + 1 + sizeof(ino) + sizeof(len) + len > end);
202	ceph_encode_8(p, 1);
203	ceph_encode_64(p, ino);
204	ceph_encode_32(p, len);
205	if (len)
206		memcpy(*p, path, len);
207	*p += len;
208}
209
210static inline void ceph_encode_string(void **p, void *end,
211				      const char *s, u32 len)
212{
213	BUG_ON(*p + sizeof(len) + len > end);
214	ceph_encode_32(p, len);
215	if (len)
216		memcpy(*p, s, len);
217	*p += len;
218}
219
220#define ceph_encode_need(p, end, n, bad)			\
221	do {							\
222		if (!likely(ceph_has_room(p, end, n)))		\
223			goto bad;				\
224	} while (0)
225
226#define ceph_encode_64_safe(p, end, v, bad)			\
227	do {							\
228		ceph_encode_need(p, end, sizeof(u64), bad);	\
229		ceph_encode_64(p, v);				\
230	} while (0)
231#define ceph_encode_32_safe(p, end, v, bad)			\
232	do {							\
233		ceph_encode_need(p, end, sizeof(u32), bad);	\
234		ceph_encode_32(p, v);				\
235	} while (0)
236#define ceph_encode_16_safe(p, end, v, bad)			\
237	do {							\
238		ceph_encode_need(p, end, sizeof(u16), bad);	\
239		ceph_encode_16(p, v);				\
240	} while (0)
241#define ceph_encode_8_safe(p, end, v, bad)			\
242	do {							\
243		ceph_encode_need(p, end, sizeof(u8), bad);	\
244		ceph_encode_8(p, v);				\
245	} while (0)
246
247#define ceph_encode_copy_safe(p, end, pv, n, bad)		\
248	do {							\
249		ceph_encode_need(p, end, n, bad);		\
250		ceph_encode_copy(p, pv, n);			\
251	} while (0)
252#define ceph_encode_string_safe(p, end, s, n, bad)		\
253	do {							\
254		ceph_encode_need(p, end, n, bad);		\
255		ceph_encode_string(p, end, s, n);		\
256	} while (0)
257
258
259#endif
260